一个人的生命究竟有多大意义，这有什么标准可以衡量吗？提出一个绝对的标准当然很困难；但是，大体上看一个人对待生命的态度是否严肃认真，看他对待劳动、工作等等的态度如何，也就不难对这个人的存在意义做出适当的估计了。
古来一切有成就的人，都很严肃地对待自己的生命，当他活着一天，总要尽量多劳动、多工作、多学习，不肯虚度年华，不让时间白白地浪费掉。我国历代的劳动人民及大政治家、大思想家等等都莫不如此。
Is there a standard to evaluate the significance of one’s life? It’s certainly difficult to offer a definite standard. But generally speaking, we can tell it by judging his attitude towards life and work, making clear whether he is serious about his life.
Throughout the history, the outstanding people were all very serious about their lives. They made best use of every minute of their lives to work and study as much as possible, never wasting their time. None of the working people and the great statesmen and thinkers were of exception.
Pollution is a problem because man, in an increasingly populated and industrialized world, is upsetting the environment in which he lives. Many scientists maintain that one of man’s greatest errors has been to equate growth with advancement. Now “growth”industries are being looked on with suspicion in case their side effects damage the environment and disrupt the relationship of different forms of life. The growing population makes increasing demands on the world’s fixed supply of air, water and land. This rise in popolation accompanied by the desire of more and more people for electriciy, water and goods results in an ever increasing amount of waste material to be disposed of. The problem has been causing increasing concern to living things and their environment. Many believe that man is not solving these problems quickly enough and that his selfish pursuit of possessions takes him past the point of no return before he fully appreciate the damage.
污染已成为问题，因为再当今人口越来越多，社会越来越工业化的世界上，人类正在污染他们居住的环境。许多科学家认为人类最大的错误是把发展和进步等同起来。现在人们以怀疑的态度看待“发展性”产业，因为它们的副作用会破坏环境，破坏各种生命之间的关系。人口的增长导致对世界上有限的空气、水和土地的需求不断增长。伴随着人口增长的是越来越多的人渴望更高的生活水平。于是对对电、水和商品的更大需求必然造成有更多的废物要处理。这个问题已经引起人们对生物及其环境的日益关注。许多人认为，人类没有尽快解决这一问题，却只顾谋求私利，以至于到了无可挽救的地步以后才充分认识到这种损害。
Whenever we visit a terminally ill patient, we cannot help being struck by his eagerness to know the truth about his condition. He does not only suffer from his illness, but also from the anxiety about its potential outcome. Although telling him the truth may risk destroying his hope, so that he may deteriorate faster, perhaps even commit suicide, a dying person has the right to know his condition and to make informed choice concerning his own health.
每当我们去探视一名患有不治之症的病人时，我们不禁为他那种急切想知道自己的真实病情的表情所震动。他不仅被疾病所折磨，也被为自己的病情可能发展的结果而焦虑所折磨。虽然若将真实病情告知他可能会使之失去希望，从而加速病情的恶化，甚至他可能自寻短见，但一个濒临死亡的病人有权知道自己的病情，有权对自己的健康状况作一个明智的判断。
To be really happy and really safe, one ought to have at least two or three hobbies, and they must all be real. It is no use startling late in life to say: “I will take an interest in this or that.”Such an attempt only aggravates the strain of mental effort. A man may acquire great knowledge of topics unconnected with his daily work, and yet hardly get any benefit or relief. It is no use doing what you like; you have got to like what you do. Broadly speaking, human beings may be divided into three classes: those who are toiled to death, those who are worried to death, and those who are bored to death. It is no use of offering the manual laborer, tired out with a hard week’s sweat and effort, the chance of playing a game of football or baseball on Saturday afternoon. It is no use inviting the politician or the professional
or business man, who has been working or worrying about serious things for six days, to work or worry about trifling things at the week-end.
要享有真正幸福和真正的平安，一个人应该至少有两种或三种嗜好，而且这种嗜好都必须是真正的爱好。到了暮年才奢谈：“我爱好这个或那个”已毫无用处了。这样的尝试只会加重精神劳累。一个人可以获得与他日常工作没有关联的某些课题的渊博之声，然而，可能难以有所获益或得到调剂。喜欢什么就干什么是无益的，你必须干哪行喜欢哪行。广而言之，人可以分为三类：有劳累至死的；有焦虑至死的；也有厌烦至死的。对于经过一周的艰辛的流汗出力的体力劳动者来说，给他们机会在周日下午去踢一场足球或打一场棒球是毫无用处的。政治家，从事专门职业的人，或商人，他们六天来为正经事操劳，担心，请他们在周末为无足轻重的事发愁是毫无益处的。
当我刚刚能够歪歪趔趔地提着一个篮子跑路的时候，我就跟在大姐的身后拣麦穗了。对我来说，那篮子未免太大，老是磕碰我的腿和地面，时不时就让我跌上一跤，我也少有拣满一篮子的时候，我看不见地里的麦穗，却总是看见蚂蚱和蝴蝶。而当我追赶它们的时候，好不容易拣到的麦穗，还会从篮子里重新掉进地里
When I was old enough to be running about on my own, I would trudge behind my elder sister to pick wheat, with a basket on my arm. The basket was always too big for me; it would bounce against my legs or the ground. Often it made me stumble. I rarely filled my basket. Either I missed the wheat stalks lying in the fields, or I was distracted by grasshoppers and butterflies. Sometimes even the stalks in my basket tumbled out as I chased after butterflies.
尽管嘴上说友谊，对运动员来说重要的仍是比赛成绩。得第一名的获金牌，第四名什么也拿不到。任何想获奥运冠军的人都得中断学业，牺牲自己的业余时间。这一点常常是观众没看到的。因此，运动员要求得到物质奖励是可以理解的。
Despite lip service paid to friendship, what matters to athletes is success. Whoever comes first wins a gold medal but anyone who comes fourth gets nothing. What the spectators sometimes fail to notice is that anyone who wants to become an Olympic champion has to break off his studies and has little spare time. Therefore, it is understandable that athletes want some tangible reward.
谁能否认海的伟大呢？我爱海，并不仅仅因为她的颜色美丽，和藏在海底那许多有趣的玩意儿，而是爱她的胸襟广阔，化污秽为清洁。她容纳无数的细流，尽管它们的颜色有黑的也有黄的，一旦流到了海的怀抱，便立刻变成碧绿的了。碧绿是代表和平，代表一种静美。一个人，哪怕他的脾气有如虎狼那么凶暴，我相信如果常住在海滨，一定会变得和羔羊一般驯良；同时，那些心胸狭隘的人，如果常与海做朋友，我相信他也会改变成豪爽，痛快的性格。There is no denying the mightiness of the sea! I love her not only because she has the beautiful hues and many intriguing objects hidden deep underneath her but also because she is broad and liberal enough to turn the foul into the pure. The numerous small rivers that she accommodates may be of black or yellow, but once they flow into her bosom, they instantly take on green signifying peace and tranquility. A person with a terrifying hot temper will become, I believe, as meek as a lamb after a long stay by the seashore. Likewise I believe a narrow-minded person will become tolerant and open-hearted if he often keeps company with the sea.
根据中国的礼仪，凡有外国客人和中国贵宾来访，都要为他们举行宴会。中国宴会的好坏是用两个因素进行评定的：一是饭菜的质量，二是品种的数量。和西方宴会不同的是，西方宴会一般只有一道主菜，再加上几个配菜；而中国的宴会有上不完的菜：有鱼，有山珍，有肉、菜、蛋以及其他各种炒菜。宴会最先上的是几道装饰得很好看的冷盘。这些冷盘一般相当于西方人的开胃菜。热菜是一道一道随做随上，摆在宴桌中间。一般普通的宴会有八道菜，而特殊的宴会则更多。
Chinese etiquette requires holding a banquet for foreign guests or important Chinese visivors. A Chinese banquet is judged by two factors --- the quality of the food and the number of different dishes. Unlike Western feasts which usually feature one main course and several side dishes, a Chinese banquet requires a seemingly endless series of
dishes including fish, fowl, meat, vegetables, eggs and combinations. To begin the meal, there are several cold plates, often in ornamental style, which correspond to Western appetizers. Hot dishes are served one at a time as they are cooked, and are placed in the center of the table. An ordinary banquet contains at least eight dishes and a special one may include many more.
The British may have long been a nation of shopkeepers but they are coming late to the business tourism．For the past century they have done the touring while their own hotels have slumbered in atmosphere and are inefficiency and even the pubs have closed before eleven. Now，somewhat to their bewilderment，they are having to act as hosts to a vast throng of guests，who，with dollars，francs and marks in their pocketsand handbag，are the most successful invaders since the Normans and considerably more welcome. They come to enjoy the antique and traditional but are often less enchanted by the accommodation and catering，which may share the antiquity. At last，even the surprised tourist industry is beginning to open its eyes．Unfortunately it sees only insoluble problems.
英国人可能早已精通生意，但其旅游业的开发却很迟。一个世纪来，是他们自己在旅游观光，而他们自家的旅馆却心安理得地躺着睡大觉，效率极低，甚至酒吧也在11点钟以前关门。如今，有点令他们迷惑不解的是，他们正在被迫接待大批的客人，这些客人口袋和手提包里装着美元、法郎和马克，是继诺曼人征服英国以来最成功的入侵者，而且要更受欢迎得多。这些人为欣赏古迹与传统习俗而来，对于这里的食宿，却往往不那么着迷，尽管这样的食宿可能带有古老的风味。终于，感到惊讶的旅游业开始觉醒了。不幸的是，它所看到的只是一些无法解决的问题。
An American will build a house in which they are going to pass his old age and sell it before the roof is on；he will plant a garden and rent it just as the trees are coming into bearing；he will clear a field and leave others to reap the harvest；he will take up a profession and leave it，settle in one place and soon go off elsewhere with his changing desires．If his private business allows him a moment’s relaxation，he will plunge at once into the whirlpool ofpolities．Then，if at the end of a year crammed with work he has a little spare leisure，his restless curiosity goes with him traveling up and down the vast territories of the United States. Thus he will travel five hundred miles in a few days as a distraction from his happiness．
一个美国人会为安度晚年去兴建一幢房子，却又会在房顶还没架上屋梁时就把它卖掉；他会在花园里植树栽花，却又会在花园快要硕果累累时把它租给别人；他会在农田中播种耕耘，却又会把收获让给他人；他会热衷于一门专业，却又会马上将其放弃；他会在某处安家落户，却又会情移念转，另寻安身之地。如果管理自家店铺后仍有片刻闲暇，美国人会一头栽进政治纷争的漩涡中。时值岁尾年首，终年忙碌的美国人竟会见缝插针，不忘休闲。于是在他们永不休止的好奇之心驱使之下，他们会畅游游美国辽阔的大地，几日内纵横数百里河山，聊以消遣，暂将快乐置于一旁。
October 1, in the morning I saw, to my great surprise, the ship had floated with high tide and was driven on shore again, much nearer the island. It was some comfort on one hand for seeing her sit upright and not broken to pieces, I hoped, if the wind abated, I might get on board, and get some food and necessaries out of her for my relief; on the other hand, it renewed my grief at the loss of my comrades, who, I imagined, if we had allstayed on board, might have saved the ship, or at least they would not have been all drowned as they were; and that had the men saved, we might perhaps have built us a boat out of the ruins of the ship, to have us carried to some other part of the world.
十月一日，早晨睁眼一看，吃了一惊，因为那只大船已经随着高潮漂了起来，被冲得离岸更近了。这件事虽然一方面使我很快慰，因为我看见它仍旧挺然直立，没有被海浪打碎，希望等风息了之后，上去弄些食物和日用品来救急，另一方面却使我重新悲痛我那些伙伴的失散，我想，假使他们当时都留在船上，我们也许可以保住我们的船，至少他们不至于被淹死；假使那些人不被淹死，我们一定可以用大船的残余部分造一个小舟，划到别处去。
The birth of the computer and its American operating systems gave English a nudge ahead; that of the Internet has
given it a huge push. Any web- linked household today has a library of information available at the click of a mouse. And ,unlike the books on its own shelves or in the public library, maybe four- fifths is written in English. That proportion may lessen, as more non-English sites spring up. But English will surely dominate
计算机及其美国操作系统的诞生触动了英语的前进；因特网的诞生则给它推了一大把。今天任何一个联网的家庭都拥有一个信息库，只待鼠标一击就可取得。而且不像家里或公共图书馆书架上的书，这里可能五分之四都是用英语写的。随着更多非英语网址的出现，这个比例可能会缩小。但英语必然会占主导地位。
The growth of electronic media and the emphasis on lifelong learning add up to tremendous opportunities for people who can combine the excitement of computer graphics and animation with educational content. This “edutainment” field will be open to everyone from the entrepreneurs who package and sell the products to computer programmers, graphic artists, animators, and educators.
对于那些能把制作计算机图表和动画的兴奋与教育内容相结合的人来说，电子传媒的发展以及强调终生学习为他们增加了众多机会。这个“寓教于乐”的领域将对每个人（从经营产品包装和行销的企业家到计算机程序编制人员、制图艺术家、漫画家和教育家）开放。、
1 All the world extended best wishes to Master Kenneth Brown of Philadelphia, who at the age of eight heard his Israeli Rhapsody played by the Philadelphia Orchestra and praised by musicians and critics. He has an excellent chance to become a successful and perhaps famous adult. 全世界的人给费城的Kenneth Brown大师送去最好的祝福，在他八岁的时候因为他的以色列狂想曲被众所周知，这个交响曲是被费城的交响乐团演奏的，受到了音乐家和评论家的称赞。他有一个极好的机会成为一个成功的也许是著名的成年人。 2 Through the ages child prodigies have been regarded by the “old wives” of tradition as unnaturally or diabolically gifted, apt to burn out young and land on the junk pile. The figures do not bear this out. Most exceptionally bright children grow into exceptionally bright adult. 古往今来的神童已经被传统的“老妇人”视为不自然的或恶魔般的天才，往往生出来有潜力的孩子生长在垃圾堆里。这些数字不足以证明这一点。也有很多特别聪明的孩子长成特别聪明的成年人。 3 For nearly forty years the Milwaukee Journal library has kept a “Child Prodigies” file. More than a hundred names are listed ---- boys and girls who broke into the news at ages three to twelve as poets, musicians, mathematics wizards, university students. More than 90 per cent of these names are forgotten by the world. Some of the cards, however, carry familiar names: Yehudi Menuhin, eight; Ruth Slenczynaska, six; Philippa Schuyler, three. They are now grown up, from their twenties into their forties and all have become noted musicians. 密尔沃基期刊库保持了“神童”的文件近四十年了。超过一百个名字被列出来了——名单里的上了新闻的男孩和女孩在3到12岁成为了诗人，音乐家，数学奇才，大学生。超过90%多的名字被世人遗忘。然而，一些名字众所周知：8岁的耶胡迪·梅纽因；6岁的露丝；3岁的菲利普。他们现在都长大了，从二十几岁到四十几岁，全部成为了著名的音乐家。 4 In a study of three hundred men and women of genius, Dr. Catherine M. Cox and her colleagues at Stanford University found that almost all of them had been unusually perceptive children, even though this fact had not always been recognized.The beloved author Oliver Goldsmith, for example, was pronounced b y his earliest teachers to be “dull, stupid, a heavy blockhead，little better than a fool whom everybody made fun of.” Actually, the teachers were too obtuse to understand the overly sensitive child; at home he was writing with surprising skill and astonishing his family. 在一个关于300多个天才男人和女人的研究中，Catherine M. Cox博士和她的斯坦福大学的同事发现：几乎所有的人都是非常有洞察力的孩子，尽管这一事实并不总是被认可。例如被人们爱戴的作家奥利弗·哥德史密斯，被他最早期的老师称为做“无聊、愚蠢的一个大笨蛋，仅仅比每个人都取笑的小傻瓜好一点”。事实上，这些老师过于迟钝去理解这些过于敏感的孩子；在家里他的超人的写作技巧震惊了他的家人。
In the case of a resistor, the voltage-current relationship is given by Ohm’s law, which states that the voltage across the resistor is equal to the current through the resistor multiplied by the value of the resistance. 就电阻来说, 电压—电流的关系由欧姆定律决定。欧姆定律指出:电阻两端的 电压等于电阻上流过的电流乘以电阻值。 2]It may be that the inductor voltage rather than the current is the variable of interest in the circuit. 或许在电路中,人们感兴趣的变量是电感电压而不是电感电流。 Viewed in this light, it will be found that the analysis of three-phase circuits is little more difficult than that of single-phase circuits. 这样看来,三相电路的分析比单相电路的分析难不了多少。 At unity power factor, the power in a single-phase circuit is zero twice each cycle. 在功率因数为 1时,单相电路里的功率值每个周波有两次为零。 It should be noted that if the polarity of point Awith respect to N ( is assumed for the positive half-cycle, then when used in the same phasor diagram should be drawn opposite to, or 180? out of phase with, . 应该注意,如果把 A 点相对于 N 的极性(定为正半周,那么在用于同一相量图中时就应该画得同相反,即相位差为 180? One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system. 对应于像广义放大器这样的电子装置,一个问题就是增益 AU 或者 AI ,它们取决于两输入端系统的内部特性。
Chapter 1 Passage 1 Human Body In this passage you will learn: 1. Classification of organ systems 2. Structure and function of each organ system 3. Associated medical terms To understand the human body it is necessary to understand how its parts are put together and how they function. The study of the body's structure is called anatomy; the study of the body's function is known as physiology. Other studies of human body include biology, cytology, embryology, histology, endocrinology, hematology, immunology, psychology etc. 了解人体各部分的组成及其功能，对于认识人体是必需的。研究人体结构的科学叫解剖学；研究人体功能的科学叫生理学。其他研究人体的科学包括生物学、细胞学、胚胎学、组织学、内分泌学、血液学、遗传学、免疫学、心理学等等。 Anatomists find it useful to divide the human body into ten systems, that is, the skeletal system, the muscular system, the circulatory system, the respiratory system, the digestive system, the urinary system, the endocrine system, the nervous system, the reproductive system and the skin. The principal parts of each of these systems are described in this article. 解剖学家发现把整个人体分成骨骼、肌肉、循环、呼吸、消化、泌尿、内分泌、神经、生殖系统以及感觉器官的做法是很有帮助的。本文描绘并阐述了各系统的主要部分。 The skeletal system is made of bones, joints between bones, and cartilage. Its function is to provide support and protection for the soft tissues and the organs of the body and to provide points of attachment for the muscles that move the body. There are 206 bones in the human skeleton. They have various shapes - long, short, cube - shaped, flat, and irregular. Many of the long bones have an interior space that is filled with bone marrow, where blood cells are made. 骨骼系统由骨、关节以及软骨组成。它对软组织及人体器官起到支持和保护作用，并牵动骨胳肌，引起各种运动。人体有206根骨头。骨形态不一，有长的、短、立方的、扁的及不规则的。许多长骨里有一个内层间隙，里面充填着骨髓，这即是血细胞的制造场所。 A joint is where bones are joined together. The connection can be so close that no movement is possible, as is the case in the skull. Other kinds of joints permit movement: either back and forth in one plane - as with the hinge joint of the elbow - or movement around a single axis - as with the pivot joint that permits the head to rotate. A wide range of movement is possible when the ball - shaped end of one bone fits into a socket at the end of another bone, as they do in the shoulder and hip joints. 关节把骨与骨连接起来。颅骨不能运动，是由于骨与骨之间的连接太紧密。但其它的关节可允许活动，如一个平面上的前后屈伸运动，如肘关节；或是绕轴心旋转运动，如枢轴点允许头部转动。如果一根骨的球形末端插入另一根骨的臼槽里，大辐度的运动（如肩关节、髋关节）即成为可能。 Cartilage is a more flexible material than bone. It serves as a protective, cushioning layer where bones come together. It also connects the ribs to the breastbone and provides a structural base for the nose and the external ear. An infant's skeleton is made of cartilage that is gradually replaced by bone as the infant grows into an adult. 软骨是一种比一般骨更具韧性的物质。它是骨连结的保护、缓冲层。它把肋骨与胸骨连结起来，也是鼻腔与内耳的结构基础。一个婴儿的骨骼就是由软骨组成，然后不断生长、
AC500kV Substation Design In China Transmission and Substation Department,CPECC Abstract:Some brief informations about AC500kV substations in China,historical data of their design and essential design principles are presented in this paper.Some technical and engineering problems of AC500kV substation design and construction are discussed.It is emphasized to introduce the500kV substation scales,main electrical connections,selection of equipment and apparatus,insulation coordination,distribution switchyard,control and protection etc.Here we also discuss the policy of project cost control at present time and a prospective view of China AC substations in future. 1.Introduction The research and design of500kV substations in China were started in1977,and the first substation was put into operation in1981.From that time,because of the rapid development of electricity demand in China,design and construction of500kV substations have a great development.Especially in recent years,due to the increase of capital investment for power system construction from the State Government,500kV power system has developed even faster.Till1998about55substations(500kV)were already put into operation,in which217transformers were installed,and the total capacity reached60410 MVA.At present,there are30substations(total capacity26500MVA)under construction.In addition,it has been planned to construction/extends30substations(33transformers,24750 MVA)in accordance with the power delivery from Three Gorges Power Plant. A complete design system of AC500kV substation in China has been gradually established based on the past design and construction experiences and the use of new technologies.This system includes design procedures,design standards,rules and regulations, design management and so on. The essential design principles are safe and reliable,technically advanced,economical and reasonable,and good quality. 2.Size of Substations China is a developing country with broad territory.The economic development is very different from one region to another.In accordance with this fact,the500kV substation size is different at different time and for different region.
1.Our big old house was closely related with the joys and sorrows of four generations. 2.I planted these roses a long, long time ago before your mother was born. 3.Many sons left home to fight against the Fascist Nazi. 4.Take the first friendly greeting and always keep it deep in your heart. 1.He has prepared answers to the questions that he expects to confront during the interview. 2.His sad story touched us so deeply that we nearly cried. 3.The two of them are walking hand in hand along the river bank, chatting, laughing, and looking happy. 4.When he heart the exciting news, tears of joy welled up in his eyes. 5.People from Shanghai can understand Suzhou dialect with ease, for Shanghai dialect and Suzhou dialect have much in common. 6.Henry and his wife are looking into the possibility of buying a new house within three years. 7.He finally gave in to his daughter’s repeated requests to further her education abroad. 8.We locked all our valuables away before we went on holiday. 9.Although we have parted from eah other, I hope that we will remain good friends and that we will care for and help each other just as we did in the past. 10.At that critical moment, the army commander summoned all the officers to work out new strategies and tactics which would make it possible to conquer the enemy. Unit 2 1.A gracious manner adds the greatest splendour to your image. 2.I firmly believed the note my guest sent me didn’t take long to write. 3.The simple phrase “Excuse me.” made most of your irritation disappear. 4.Being on time is a virtue which belongs not only to the past but also to the present. 5.Y ou shouldn’t accept the other person’s presence without thinking of its importance. 6.Good manners produce the same feelings or actions in others. 1.I am sorry I am late; I was at a meeting and couldn’t get away. 2.At the concert whnever a singer finished singing a beautiful song, the audience would burst into loud cheers to show their appreciation. 3.As a stylish dresser, she is always wearing stylish clothes, but she seldom cares about what she eats or drinks. 4.The nurse tells me that the doctors have done wonders for your heart disease. 5.When awarding the prize, the chairman complimented the winner on his great contribution to mankind. 6.This problem has bothered the experts for many years. 7.The crowd of demonstrators melted away when the police arrived. 8.Since punctuality is a good habit, we should pay much attention to it and make great efforts to cultivate this good habit. 9.The old man cherishes that girl, as if she were his own daughter. 10.It is just a routine physical checkup, nothing to get worried about.
第二部分 控制理论 第1章 1.1控制系统的引入 人类控制自然力量的设计促进人类历史的发展,我们已经广泛的能利用这种量进行在人类本身力量之外的物理进程?在充满活力的20世纪中,控制系统工程的发展已经使得很多梦想成为了现实?控制系统工程队我们取得的成就贡献巨大?回首过去,控制系统工程主要的贡献在机器人,航天驾驶系统包括成功的实现航天器的软着陆,航空飞机自动驾驶与自动控制,船舶与潜水艇控制系统,水翼船?气垫船?高速铁路自动控制系统,现代铁路控制系统? 以上这些类型的控制控制系统和日常生活联系紧密,控制系统是一系列相关的原件在系统运行的基础上相互关联的构成的,此外控制系统存在无人状态下的运行,如飞机自控驾驶,汽车的巡航控制系统?对于控制系统,特别是工业控制系统,我们通常面对的是一系列的器件,自动控制是一个复合型的学科?控制工程师的工作需要具有力学,电子学,机械电子,流体力学,结构学,无料的各方面的知识?计算机在控制策略的执行中具有广泛的应用,并且控制工程的需求带动了信息技术的与软件工程的发展? 通常控制系统的范畴包括开环控制系统与闭环控制系统,两种系统的区别在于是否在系统中加入了闭环反馈装置? 开环控制系统 开环控制系统控制硬件形式很简单,图2.1描述了一个单容液位控制系统, 图2.1单容液位控制系统 我们的控制目标是保持容器的液位h 在水流出流量V 1变化的情况下保持在一定 可接受的范围内,可以通过调节入口流量V 2实现?这个系统不是精确的系统,本系 统无法精确地检测输出流量V 2,输入流量V 1以及容器液位高度?图2.2描述了这 个系统存在的输入(期望的液位)与输出(实际液位)之间的简单关系, 图2.2液位控制系统框图 这种信号流之间的物理关系的描述称为框图?箭头用来描述输入进入系统,以及
The patient-physician interaction proceeds through many pases of clinical reasoning and decision making . The interaction begins with an elucidation of complaints or concerns , followed by inquiries or physical examination , ordering of diagnostic tests , integration of clinical findings with the test results , understanding of the risks and benefits of the possible courses of action , and careful consultation with the patient and family to develop future plans . Physicians increasingly can call on a growing literature of evidence-based medicine to guide the process so that benefit is maximized , while respecting individual variations among different patients. 医患沟通贯穿于临床推论和临床决策的各个阶段.医患沟通始于主诉的阐述或关心的表达,并以越来越精确的方式,通过学问或评估得以继续,这一过程通常需要仔细的病史(采集)和体格检查,安排诊断性实验,并使实验结果与临床发现一体化,以及对可能所采取行动的风险和好处的理解，与病人及其家庭之间细致的商讨以产生将来的计划。医生越来越（趋于）访问日益增多的循证医学文献去指导这个过程，以使取得最大的收益，同时对于不同的病人充分考虑个体的不同变化。 Chapter 8 第四段 Fourth , cognitive impairment increases in prominence as people age. Cognitive impairment is a risk factor for a wide range of adverse outcomes ,including falls , immobilization , dependency , institutionalization , and mortality . Cognitive impairment complicates diagosis and requires additional care giving to ensure safety . Chapter 21 第六段 A new device for visualizing the entire gastrointestinal mucosa consists of a small camera in an ingestable capsule that transmits images to receivers attached to the patient~s abdomen diagnostic yield of capsule enteroscopy is not yet clear,but this approach may potentially visualize segments of the small bowel that were previously inaccessible . No therapeutic maneuvers are possible with the device.
近年来基于2010中国国家血压参考文献的中国儿童和青少年高血压患病率研究 儿童高血压是一种严重的公共卫生问题在世界范围内,尤其是在中国。流行病学研究表明,儿童高血压可以追踪到成年。此外,儿童高血压与成年发病率和死亡率的增加是密切相关的。2010年以前,在中国没有共识定义儿童高血压,这阻碍了中国不同的地区高血压患病率的比较。2010年,Mi 等人通过研究112227名3-18岁儿童和青少年的血压，获得了血压(BP)参考年龄和性别使用的参考文献。根据这个国家的定义,童年高血压定义为收缩压(SBP)和/或舒张压(菲律宾) 年龄和性别的百分比95以上。在本研究中,我们目的是执行使用系统回顾描述2010年中国的不同地区儿童和青少年高血压的患病率的应用。 PubMed和Wanfang数据库寻找合格的文献。搜索条件是(“高血压”或“高血压”)和(“孩子”或“青少年”或“学生”)和(“中国”或“中国人”)。从2010年1月(2010年后出版的, Mi 等人研究的中国国家血压引用文献.[5]),到2014年4月出版的刊物，语言仅限于英语和汉语。入选标准是:(1) 3-18岁的中国儿童和青少年;(2)使用2010中国血压参考标准;(3)测量收缩压和舒张压值至少在同一情况下三次;(3)自2008年以来进行的调查;(4)如果出版包括在不同年份的调查,只包括最近的调查。文献检索后,共有11项研究，（参与者总数是444214)(1、2、6-14)都包含在本研究中。纳入研究的特点总结在表1。高血压患病率在中国不同的区域有显著的不同， (图1)。中国北方城市包括北京(18.2%)或山东高血压患病率(23.3%)高于南部城市包括上海、湖南长沙、和海南(从3.1%升至11.2%)和农村地区。高血压患病率的升高可能很大程度上归因于中国北方饮食盐摄入量。例如,在山东农村成年人的每日摄取食盐约13 g,高于世界卫生组织(少于5克/天)推荐的两倍。 此外,在中国北方高血压高发病率中，肥胖是另一个重要的危险因素。在山东,大约16%的男生和8%的女生肥胖[16],而在湖南省长沙市相应的数据分别是7%和3%。我们还发现，基于中国健康和营养调查的数据和中国全国学生体质与健康调查,整体的高血压患病率14%。我们的研究有两个优点，首先,所有研究包括之后研究都采用相同的标准，即中国国家高血压参考文献。第二,所有调查研究在相似的时期,即从2008年到2010年，因此,流行是最新的,具有可比性。然而,应该注意研究中几个限制。首先,所有高血压患病率的研究仅为同一情况,除了孟等人[6] 在三个不同的时期提供的变化患病率。因此, 我们现在报告中的发病会高估了中国儿童和青少年的高血压真正的发病率。孟等人[6]表明, 在中国北京，3-18岁儿童和青少年高血压的患病率分别是三次分别是18.2%,5.1%,和3.1%。第二, 虽然我们列举了中国几个有限地区对肥胖患病率和消费的盐摄入量，但是中国不同地区高血压发病率不同，我们没有数据表明流行的原因是什么。第三,我们只研究几个儿童高血压高发地区, 需要进一步全面研究中国其他地区高血压患病率。第四,我们只报道汉族中国儿童高血压的患病率，而他少数民族没有类似报告。中国是一个多民族的国家有56个民族,但汉族占中国人口总数的92%左右。目前的研究表明,调查儿童和青少年高血压患病率和区域分布是很重要的，应该建立特定的干预策略来对抗高血压流行。主要措施应该建议控制体重,减少盐的摄入量,特别是在中国北方,以降低中国不同地区儿童高血压患病率。
Unit 1 1. 他相当足球明星的梦想随着时间的推移慢慢消退了。 His dream of becoming a football star faded out as time went by. 2. 一架波音747 飞机没有升到足够的高度以飞越那座高山，转瞬间一头撞向大山爆炸了。机上无人生还。 A Boeing 747 aircraft didn 't gain enough height to clear the mountain. In a twinkling, it crashed into the mountain and blew up. No one survived the accident. 3. 学生们可以很容易地获得图书馆的资源，所以他们应该充分地利用好图书馆。Students have easy access to the resources in the library, so they are supposed to make the best of it. 4. 当时世界上最豪华的游轮泰坦尼克号在她前往美国的途中撞到了冰山，结果轮船沉没在大西洋中，成百上千的人死于这场海难。 Titanic, the most luxurious ship in the world at that time , hit an iceberg when she was under way to the US. Consequently, the ship sank into the Atlantic Ocean and thousands of people died in this shipwreck. 5. 每天夏天，游客们都涌向这一著名的海滩。来此享受日光浴的游客像沙丁鱼一样挤满了海滩。 Every summer, all the tourists pour into this famous beach. They lie packed like sardines on the beach to enjoy the sunbathing. 6. 他们曾经到圣路易斯去过一次，对于哪里的新奇事物稍微知道一个大概，可是现在他们的光荣时代已经成过去了。他们从此自知没趣，再也不说话了，而且每逢这个毫不留情的机匠走过来的时候，他们就知道赶快躲开。 The have been to St. Louis once and have a vague general knowledge of its wonders, but the day of their glory is over now. They lapse into humble silence and learn to disappear when the ruthless engineer approaches. Unit 2 1. 有些网络专家认为因特网可以防止战争、减少污染，还能克服种种形式的不平等。Some cyber gurus claim that the Internet will prevent wars, reduce pollution, and combat various forms of inequality. 2. 不可否认，因特网可以增进交流，但他却无法消除战争，因为战争的爆发并不仅仅是由于不同种族间缺乏充分理解而引起的。 Although the Internet undeniably fosters communication, it will not put an end to war, since wars are by no means caused simply by the failure of different peoples to understand each other adequately. 3. 只有当网上的活动能够真正取代现实世界中的行为时，因特网才能帮助节约能源，减少污染。 The Internet can help reduce energy consumption and pollution only if doing things online genuinely displaces real-world activities. 4. 穷人不用因特网并不是因为他们买不起，而是因为他们缺乏必要的技能来有效地利用它，所以提高老百姓的文化水平要比给他们提供上网机会更有意义。 The poor are not shunning the Internet because they cannot afford it. The problem is that they lack the skills to exploit it effectively. Therefore, it makes more sense to aim for universal literacy than universal Internet access.
Table of Contents Uuit 1 What is Geomatics? （什么是测绘学） (2) Unit 2 Geodetic Surveying and Plane Surveying（大地测量与平面测量） (6) Unit 3 Distance Measurement（距离测量） (10) Unit 4 Angle and Direction Measurement（角度和方向测量） (14) Unit 5 Traversing （导线测量） (17) Unit 6 Methods of Elevation Determination（高程测量方法） (21) Unit 7 Robotic Total Station （智能型全站仪） (25) Unit 8 Errors in Measurement（测量工作中的误差） (29) Unit 9 Basic Statistical Analysis of Random Errors (32) Unit 10 Accuracy and Precision （准确度和精度） (35) Unit 11 Least-Squares Adjustment (38) Unit 12 Geodesy Concepts (40) Unit 13 Geoid and Reference Ellipsoid (42) Unit 14 Datums, Coordinates and Conversions (44) Unit 15 Map Projection (46) Unit 16 Gravity Measurment (48) Unit 17 Optimal Design of Geomatics Network (50) Unit 18 Construction Layout （施工放样） (53) Unit 19 Deformation Monitoring of Engineering Struvture (56) Unit 20 Understan ding the GPS（认识GPS） (59) Uuit 21 Understanding the GPS (II) 认识GPS(II) (62) Unit 22 Competition in Space Orbit（太空轨道上的竞争） (64) Unit 23 GIS Basics（GIS 的基础） (69) Unit 24 Data Types and Models in GIS GIS中的数据类型和模型 (75) Unit 25 Digital Terrain Modeling（数字地面模型） (79) Unit 26 Applications of GIS (83) Unit 27 Developments of photogrammetry (87) Unit 28 Fundamentals of Remote Sensing （遥感的基础） (90) Unit 29 Digital Image Processing and Its Applications in RS (94) Unit 30 Airborne Laser Mapping Technology（机载激光测图技术） (99) Unit 31 Interferometric SAR(InSAR) (102) Unit 32 Brief Introduction toApplied Geophysics (104) Unit 33 Origon of Induced Polarization (105) Unit 34 International Geoscience Organization (108) Unit 35 Prestigious Journals in Geomatics (110) Unit 36 Relevant Surveying Instrument Companies (115) Unit 37 Expression of Simple Equations and Scientific Formulsa (116) Unit 38 Professional English Paper Writing (119) Unit 39 Translation Techniques for EST (127)